1. Field of the Invention
The present invention relates to a method and apparatus for performing intra planar mode type prediction decoding on digital video data that has been encoded using an intra planar mode type prediction.
2. Discussion of the Related Art
A digital video signal is comprised of a sequence of digital video frames that are a representation of an original RGB video signal. As part of the analog to digital signal transformation, each frame of the original RGB video signal is encoded into the digital video frames of data that comprise the digital video signal. The purpose of the encoding process is to calculate as accurate a digital prediction of the original RGB video signal as possible while also attempting to maximize a compression of the binary data that is the digital representation of the original RGB video signal. While there exists both inter prediction methods and intra prediction methods for encoding a video signal, the present invention is only concerned with the intra prediction method that is also referred to as a spatial prediction method.
In order to accomplish the encoding process, an encoding unit will process a prediction on a portion of an original video frame in order to encode it into digital video data. The resulting encoded digital video data is referred to as a prediction unit. A plurality of prediction units will typically comprise a tree block of video data, a plurality of tree blocks will typically comprise a slice of video data and a plurality of slices will then typically comprise a frame of digital video data, although other configurations are possible. Pertaining specifically to the intra prediction methods that rely on spatial predictions, a current prediction unit that is being processed will be predicted by referencing previously predicted samples that spatially neighbor the current prediction unit. Once all of the digital video frames have been predicted and encoded, the digital video program is said to be fully compressed and ready for storage or transmission as digital video data or a signal. Along with the actual digital video data, the encoding unit will also include identifying information that indicates which prediction mode was applied to predict each prediction unit of video data.
A decoding unit is then tasked with performing the decoding, or decompression, of the digital video data/signal. The decoding is processed by applying the same prediction mode processing on each prediction unit as was applied by the encoding unit. This is accomplished by parsing the identifying information and determining the proper prediction mode that is identified for predicting each prediction unit of video data. By applying the proper prediction on each of the prediction units of video data, the decoding unit is able to successfully reconstruct the original video. The decoding unit is thus assigned the task of reconstructing the digital video signal into a displayable representation of the original video signal. According to the intra prediction mode for decoding a prediction unit, previously reconstructed samples from previously reconstructed prediction units will be referenced to reconstruct samples of a current prediction unit that is currently being processed by the decoding unit.
Of the many available intra prediction modes for predicting a prediction unit of digital video data, the present invention is concerned with the intra planar prediction mode. The intra planar mode prediction is generally known to first predict a single sample within a current prediction unit by referencing neighboring blocks that have been previously reconstructed. Then after predicting the first sample within the current prediction unit, the remaining samples of the current prediction unit are predicted by referencing the predicted first sample within the current prediction unit and reconstructed samples from the blocks that neighbor the current prediction unit.